The present invention relates generally to refrigerators, and more specifically to compressors, coolant pumps and controls of refrigerators.
Generally, the cooling system of a refrigerator includes an evaporator, a compressor, a condenser, and an expansion device.
It is common in the art of refrigerators to provide an automatic icemaker. In a “side-by-side” type refrigerator where the freezer compartment is arranged to the side of the fresh food compartment, the icemaker is usually disposed in the freezer compartment and delivers ice through an opening in the access door of the freezer compartment. In this arrangement, ice is formed by freezing water with cold air in the freezer compartment, the air being made cold by the cooling system or circuit of the refrigerator. In a “bottom freezer” type refrigerator where the freezer compartment is arranged below a top fresh food compartment, convenience necessitates that the ice be dispensed through an opening in the access door of the fresh food compartment, rather than through the access door of the freezer compartment. It is known in the art that a way to form ice in this configuration is to deliver cold air, which is cooled by the evaporator of the cooling system, to an icemaker located in the fresh food compartment which may be on or near the access door to maintain the icemaker at a temperature below the freezing point of water.
One known approach is to use a thermoelectric device to make ice in the fresh food compartment. Thermoelectric icemakers are well known and commercially available. In one specific embodiment, a freezer air duct extends from the freezer compartment and into the fresh food compartment, and a small stream of air from the freezer compartment acts as a coolant for the heat released from the thermoelectric device. In the example embodiment, the freezer air performs multiple functions including cooling an ice storage bin, cooling the thermoelectric device and also for controlling the temperature of the fresh food compartment.
A thermoelectric device is also typically coupled with the ice mold body, the ice mold body having cavities for forming ice cubes, to heat the mold body before harvest of the ice cubes from the cavities to a storage area. Harvest of ice cubes involves removing the cubes from the ice mold by a mechanical force so that new ice cubes can be formed within the mold. The thermoelectric device heats the ice mold body to a temperature above the freezing point of water so that the ice cubes melt slightly and can be ejected by an ejection mechanism more easily.
After ejection of ice cubes, they are typically stored in a closely located bin. The temperature in the bin is typically not monitored, and remains cool by its placement within an icemaker compartment. Typically, temperature within the icemaker compartment is set by the temperature of the air from the freezer compartment that is distributed to it. This leaves no way for the icemaker compartment or the components therein to control the temperature or flow of the coolant distributed to it.
Typically, a refrigerator is provided with an evaporator or cooling coil that receives coolant from the refrigerator in a closed loop configuration where the coolant is expanded to a low pressure and temperature state for circulation through the heat exchanger to cool the space and objects within the refrigeration device.
Typically the compressor and a coolant pump work independently of each other, and either one, both or neither may be operating at a given point in time. This presents a challenge of poor coolant distribution while the compressor is activated and the coolant pump is deactivated, creating a situation where coolant in a typical vapor compression cycle gets colder but that coolant would not cool other areas of the refrigerator, specifically an icemaker compartment in a fresh food section of the refrigerator.
Generally the temperature within the ice storage bin is not monitored or controlled directly. There are several sources of heat within the icemaker compartment and there are periods when the icemaker compartment and ice storage bin specifically, are not being cooled. These factors cause the melting of stored ice cubes and liquid water creation in the ice storage bin. Upon further cooling and subsequent refreezing, the water and remaining ice cubes clump together, forming a mass of solid ice. Clumping of ice is undesirable because it hinders dispensing of the ice to the user.
Therefore, an ability to keep the temperature in the ice storage bin below freezing at all times is desired. In addition the convenience of being able to increase the rate of ice production during times of heavy usage is desirable.